This invention relates to a pressure control device for offset printing machines, and more particular to an improved device for adjusting the printing pressure of a pressure cylinder to printing paper.
In conventional offset printing machine, the printing control for the thickness of printing paper has been done by the rotation of nuts and double nuts fixed to shafts onto which springs for elastically pressing a pressure cylinder to a rubber bracket are provided. However, this manner of adjustment is only possible with the printing machine in a pause mode, and moreover requires some tools. Thus, adjustment has taken considerable time and is tedious.
Therefore, an object of the invention is to provide an improved device which is capable of adjusting the pressure even while a printing machine is in operation as well as in the pause mode.
Another object of the invention is to provide an improved device which is capable of adjusting the pressure corresponding to the paper thickness just by the rotation of an adjustor dial without any tools.
It is a still further object of the invention to provide a pressure control device which automatically adjusts the pressure for thin paper or ordinary thickness paper irrespective of some variation in the thickness.
The above and other objects and the advantages of the invention will be apparent from the description taken in conjunction with the accompanying drawings.